In transmission and reception of television signals, interlaced scan is generally employed. This technique uses two fields to create a frame. One field called top field contains all odd-numbered lines in a television image; the other called bottom field contains all even-numbered lines in the television image. After the interlaced scan to the top field and the bottom field, scan data corresponding to the top field and scan data corresponding to the bottom data are combined to constitute a frame. In such way, video stream is formed. However, the formed video stream can exhibit interlacing effects. Therefore, de-interlacing of television signals is required in television signal processing.
In existing techniques, directions of missing pixels are deduced based on known pixels, and pixel values of the missing pixels are obtained by performing interpolation to the known pixels at the deduced directions.
However, the existing techniques may have following disadvantages.
(1) When hardware sources are limited, for example, there are only two lines of data in a vertical direction (that is, only one row of pixels in a top filed have known pixel values and only one row of pixels in a bottom field have known pixel values, respectively), almost no algorithm can ensure accuracy of direction determination. Further, to some details, although related data are many enough, interpolation can not be well performed based on direction determination. That is because the details do not have a clear direction (such as some corners in characters). In fact, a portion of images in a video may retain absolutely static or relatively static (global motion).
(2) Direction determination in a motion scenario is great difficulty in de-interlacing algorithm, especially when a direction of images presents a relatively small angle.